Synthesis and properties of aromatic polyimide,poly(benzoxazole imide), and poly(benzoxazole amide imide)

Two series of heterocyclic aromatic polymers were synthesized from 4,4′‐(4,4′‐isopropylidenediphenoxy)bis(phthaltic anhydride) and 2,2′‐bis(3,4‐dicarboxyphenyl)hexafluoropropane dianhydride by two‐step method. The inherent viscosities were in the range of 24–45 cm³/g. The effects of the rigid benzoxazole group in the backbone of copolymer on the thermal, mechanical, and physical properties were investigated. These polymers exhibit good thermal stability. The temperatures of 5% weight loss (T₅) of these polymers are in the range of 403–530°C in air and 425–539°C in nitrogen. The chard yields of these polymers are in the range of 15–24% in air and 54–61% in nitrogen. These polymers also have high glass‐transition temperatures and a low coefficient of thermal expansion and good mechanical properties. The poly(benzoxazol imide) has a higher tensile strength and modulus than those of neat polyimide. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Novel trifluoromethyl‐containing poly(amide–imide)s: Organosolubility,optical behavior,thermostability, and crystallinity

A new dicarboxylic acid monomer, 2,6‐bis(1,3‐dioxo‐5‐carboxyisoindolin‐2‐yl)‐4,4′‐bis(trifluoromethyl)‐1,1′‐diphenyl ether (IFDPE), bearing two preformed imide rings was synthesized via a three‐step manner from 4‐(trifluoromethyl)phenol and 4‐chloro‐3,5‐dinitrobenzotrifluoride. The monomer IFDPE was then used to prepare a series of novel trifluoromethyl‐containing poly(amide–imide)s via a direct phosphorylation polycondensation with various aromatic diamines. The intrinsic viscosities of the polymers were found to be in the range 0.86–1.02 d/g. The weight‐ and number‐average molecular weights of the resulting polymers were determined with gel permeation chromatography. The polymeric samples were readily soluble in a variety of organic solvents and formed low‐color, flexible thin films via solution casting. The values of the absorption edge wavelength were determined by ultraviolet–visible spectroscopy, and all of the resulting poly (amide–imide)s films exhibited high optical transparency. The resulting polymers showed moderately high glass‐transition temperatures in the range 295–324°C and had 10% weight loss temperatures in excess of 524°C in nitrogen. The crystallinity extents were qualitatively investigated with wide‐angle X‐ray diffraction measurements. Scanning electron microscopy images revealed an agglomerated bulk with nonuniformity on the surface. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Novel thermally stable poly(ether imide ester)s from 2,6‐bis (4‐aminophenoxy) pyridine

2,6‐Bis (4‐aminophenoxy) pyridine was prepared via reaction of 4‐aminophenol with 2,6‐dichloropyridine in the presence of potassium carbonate in N‐methyl‐2‐pyrrolidone (NMP). This pyridine‐based ether diamine was reacted with two moles of trimellitic anhydride to synthesize related diimide‐diacid (DIDA). A high temperature solution polycondensation reaction of DIDA with different diols in the presence of triethylamine hydrochloride in dichlorobenzene resulted in different poly(ether imide ester)s. The monomer and polymers were fully characterized, and the physical and thermal properties of the polymers were studied. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 570–576, 2005     

Synthesis and properties of poly(ether imide)s derived from 2,5‐bis(3,4‐dicarboxyphenoxy)biphenyl dianhydride and aromatic ether–diamines

A series of poly(ether imide)s (PEIs) with light colors and good mechanical properties were synthesized from 2,5‐bis(3,4‐dicarboxyphenoxy)biphenyl dianhydride and various aromatic ether–diamines via a conventional two‐step polymerization technique that included ring‐opening polyaddition at room temperature to poly(amic acid)s (PAAs) followed by thermal imidization. The precursor PAAs had inherent viscosities ranging from 0.71 to 1.19 dL/g and were solution‐cast and thermally cyclodehydrated to flexible and tough PEI films. All of the PEI films were essentially colorless, with ultraviolet–visible absorption cutoff wavelengths between 377 and 385 nm and yellowness index values ranging from 10.5 to 19.9. These PEIs showed high thermal stabilities with glass‐transition temperatures of 206–262°C and decomposition temperatures (at 10% weight loss) higher than 478°C. They also showed low dielectric constants of 3.39–3.72 (at 1 MHz) and low water absorptions below 0.85 wt %. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation of novel pyridine‐based,thermally stable poly(ether imide)s

Two aromatic, pyridine‐based ether diamines were prepared by the nucleophilic aromatic substitution reaction of 4‐aminophenol and 5‐amino‐1‐naphthol with 2,6‐dichloropyridine in N‐methyl‐2‐pyrrolidone as a solvent. Polycondensation reactions of the obtained diamines with pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, and hexafluoroisopropylidene diphthalic anhydride resulted in six pyridine‐based, thermally stable poly(ether imide)s. The prepared monomers and polymers were characterized by common spectroscopic methods. The physical and thermal properties of the polymers, including the thermal behavior, thermal stability, solubility, and solution viscosity, were studied. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 22–26, 2004     

Structure and properties of aromatic poly(benzimidazole‐imide) copolymer fibers

A series of co‐polyimide fibers were prepared by thermal imidization of copolyamic acids derived from 3,3′,4,4′‐biphenyltertracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA) in various molar ratios with 2‐(4‐aminophenyl)?5‐aminobenzimidazole (BIA). The dynamic mechanical behaviors of these polyimide (PI) fibers revealed that the glass transition temperature (T_g) was significantly improved upon increasing PMDA content. Heat‐drawing process led to dramatic change on the glass transition behavior of BPDA/BIA system, but had a small impact on BPDA/PMDA/BIA co‐polyimide fibers. This difference for PI fibers is attributed to the different degree of ordered structure of the fibers affected by heat‐drawing. The incorporation of PMDA obviously improved the dimensional stability against high temperature, due to the restricted movement of polymer chains. In addition, the obtained fibers show excellent mechanical and thermal properties because of the strong hydrogen bonding due to the incorporation of benzimidazole moieties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41474.     

Synthesis and properties of fluorinated aromatic poly(amide imide)s based on 4,4′‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzophenone and various bis(trimellitimide)s

A CF₃‐containing diamine, 4,4′‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzophenone ( 2 ), was synthesized from 4,4′‐dihydroxybenzophenone and 2‐chloro‐5‐nitrobenzotrifluoride. Imide‐containing diacids ( 3 and 5B_a – 5B_g ) were prepared by the condensation reaction of aromatic diamines and trimellitic anhydride. Then, two series of novel soluble aromatic poly(amide imide)s (PAIs; 6A_a – 6A_k and 6B_a – 6B_g ) were synthesized from a diamine ( 4A_a – 4A_k or 2 ) with the imide‐containing diacids ( 3 and 5B_a – 5B_g ) via direct polycondensation with triphenyl phosphate and pyridine. The aromatic PAIs had inherent viscosities of 0.74–1.76 dL/g. All of the synthesized polymers showed excellent solubility in amide‐type solvents, such as N‐methyl‐2‐pyrrolidone and N,N‐dimethylacetamide (DMAc), and afforded transparent and tough films by DMAc solvent casting. These polymer films had tensile strengths of 90–113 MPa, elongations at break of 8–15%, and initial moduli of 2.0–2.9 GPa. The glass‐transition temperatures of the aromatic PAIs were in the range 242–279°C. They had 10% weight losses at temperatures above 500°C and showed excellent thermal stabilities. The 6B series exhibited less coloring and showed lower yellowness index values than the corresponding 6A series. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:3641–3653, 2006     

New poly(amide imide imide)s based on tetraimide dicarboxylic acid condensed from 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride,m‐aminobenzoic acid,and 4,4″‐oxydianiline and various aromatic diamines

A series of new, organosoluble, and light‐colored poly(amide imide imide)s were synthesized from tetraimide dicarboxylic acid ( I ) and various aromatic diamines by direct polycondensation with triphenyl phosphite and pyridine as condensing agents. I was prepared by the azeotropic condensation of 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride, m‐aminobenzoic acid, and 4,4′‐oxydianiline at a 2/2/1 molar ratio in N‐methyl‐2‐pyrrolidone (NMP)/toluene. The thin films cast from N,N‐dimethylacetamide (DMAc) had cutoff wavelengths shorter than 400 nm (365–394 nm) and color coordinate b* values between 13.10 and 36.07; these polymers were lighter in color than the analogous poly(amide imide)s and isomeric polymers. All of the polymers were readily soluble in a variety of organic solvents, including NMP, DMAc, N,N‐dimethylformamide, dimethyl sulfoxide, and even less polar dioxane and tetrahydrofuran. The cast films exhibited tensile strengths of 90–104 MPa, elongations at break of 7–22%, and initial moduli of 1.9–2.4 GPa. The glass‐transition temperatures of the polymers were recorded at 274–319°C. They had 10% weight losses at temperatures beyond 520°C and left more than a 50% residue even at 800°C in nitrogen. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 669–679, 2003     

Facile synthesis of novel optically active poly(amide‐imide)s containing N,N′‐(pyromellitoyl)‐bis‐l‐phenylalanine diacid chloride and 5,5‐disubstituted hydantoin derivatives under microwave irradiation

Pyromellitic dianhydride (1,2,4,5‐benzenetetracarboxylic acid 1,2,4,5‐dianhydide) (1) was reacted with L‐phenylalanine (2) in a mixture of acetic acid and pyridine (3 : 2) at room temperature, then was refluxed at 90–100°C and N,N′‐(Pyromellitoyl)‐bis‐L ‐phenylalanine diacid (3) was obtained in quantitative yield. The imide‐acid (3) was converted to N,N′‐(Pyromellitoyl)‐bis‐L ‐phenylalanine diacid chloride (4) by reaction with thionyl chloride. Rapid and highly efficient synthesis of poly(amide‐imide)s (6a–f) was achieved under microwave irradiation by using a domestic microwave oven from the polycondensation reactions of N,N′‐(Pyromellitoyl)‐bis‐L ‐phenylalanine diacid chloride (4) with six different derivatives of 5,5‐disubstituted hydantoin compounds (5a–f) in the presence of a small amount of a polar organic medium that acts as a primary microwave absorber. Suitable organic media was o‐cresol. The polycondensation proceeded rapidly, compared with the conventional melt polycondensation and solution polycondensation, and was almost completed within 10 min, giving a series of poly(amide‐imide)s with inherent viscosities about 0.28–0.44 dL/g. The resulting poly(amide‐imide)s were obtained in high yield and are optically active and thermally stable. All of the above compounds were fully characterized by means of FTIR spectroscopy, elemental analyses, inherent viscosity (η_inh), solubility test and specific rotation. Thermal properties of the poly(amide‐imide)s were investigated using thermal gravimetric analysis (TGA). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 516–524, 2004     

γ‐Butyrolactone‐processable high‐modulus poly(ester imide)s

γ‐Butyrolactone (GBL)‐processable high modulus heat‐resistant materials were developed in this work. The polyaddition of an ester‐containing tetracarboxylic dianhydride, i.e. hydroquinone bis(trimellitate anhydride) (TAHQ), and 2,2′‐bis(trifluoromethyl)benzidine (TFMB) in GBL resulted in gelation in the initial reaction stage. The incorporation of a methyl group to TAHQ (M‐TAHQ) allowed polymerization with TFMB in GBL and led to a homogeneous poly(ester imide) (PEsI) precursor solution with a short pot life of 3 days, whereas a simple copolymerization approach using bulky/flexible comonomers to TAHQ/TFMB was less effective. PEsI precursors (PEsAAs) were prepared from TFMB, M‐TAHQ and a minor fraction of 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA) or a fluorene‐containing tetracarboxylic dianhydride. These PEsAA systems showed drastically improved GBL solution stability. In particular, the M‐TAHQ(80);6FDA(20)/TFMB copolymer system provided a PEsAA film with a very high light transmittance at 365 nm (>70%). A photosensitive film composed of this matrix resin and diazonaphthoquinone provided a clear positive‐tone pattern by development in a 2.38 wt% tetramethylammonium hydroxide aqueous solution at room temperature with a high dissolution contrast. The thermally cured PEsI film achieved a very high tensile modulus (>5 GPa) as the present target with other desirable properties, i.e. sufficient film flexibility, a relatively low coefficient of thermal expansion, a high T_g and low water absorption. The present materials can be promising candidates as novel buffer coat films in semiconductor applications. Copyright © 2011 Society of Chemical Industry     

Microwave‐assisted synthesis of high‐molecular‐weight poly(ether imide)s by phase‐transfer catalysis

A facile and rapid polycondensation reaction of disodium bisphenol A with bis(chlorophthalimide)s was preformed with a domestic microwave oven in o‐dichlorobenzene by phase‐transfer catalysis. The polymerization reactions, in comparison with conventional heating polycondensation, proceeded rapidly and were completed within 25 min. The polymerizations gave the corresponding poly(ether imide)s with inherent viscosities of 0.55–0.92 dL g^?1. The effects of various factors on the polymerization, such as the amount of the catalyst, the reaction time, and the microwave power were studied. The properties of the polymers were briefly characterized. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2415–2419, 2004     

Synthesis,characterization, and applications of novel additives of polysiloxane containing N,N′‐bis(diphenylsilyl)tetraphenylcyclodisilazane

Three N,N′‐bis(diphenylsilyl)tetraphenylcyclodisilazane‐based derivatives, N,N′‐bis(3,3,3‐trimethyl‐1,1‐diphenyl‐disiloxanyl)tetraphenylcyclodisilazane, N‐(3,3‐dimethyl‐1,1‐diphenyl‐3‐vinyl‐disiloxanyl)‐N′‐(3,3,3‐trimethyl‐1,1‐diphenyl‐disiloxanyl)‐tetraphenylcyclodisilazane, and N,N′‐bis‐(3,3‐dimethyl‐1,1‐diphenyl‐3‐vinyl‐disiloxanyl) tetraphenylcyclodisilazane, were synthesized. These compounds were synthesized in an easy and effective route. X‐ray single‐crystal diffraction analyses showed that the four‐member rings were planar rings, and the structures are different with the different substitution. The compound N,N′‐bis‐(3,3‐dimethyl‐1,1‐diphenyl‐3‐vinyl‐disiloxanyl) tetraphenylcyclodisilazane was added to the silicone rubber as additive to enhance the thermal stability greatly increased the thermal stability of the silicone rubber, without altering the glass transition temperature. The weight loss at 350°C in nitrogen atmosphere for 24 h reduced from 55.8% for 0 wt % to 9.8% for 10 wt % addition N,N′‐Bis‐(3,3‐dimethyl‐1,1‐diphenyl‐3‐vinyl‐disiloxanyl)tetraphenylcyclodisilazane. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Secondary dopants modified PEDOT‐sulfonated poly(imide)s for high‐temperature range application

Poly(3,4‐ethylenedioxythiophene) (PEDOT) was polymerized using sulfonated poly(amic acid)s templates (SPAA1 and SPAA2) by batch operation. The new method was invented to enhance conductivities (ca. 100 ‐ to 2000‐fold) and with less reaction time from previous work (7 days vs. 3 days). Moreover, to increase the conductivity, many dopants were introduced as secondary doping compared with DMF, D ‐sorbitol, and surfynol that were previously used. After annealing at 180°C for 10 min, PEDOT‐SPAA1 and PEDOT‐SPAA2 doped with benzo‐1,4‐dioxan and quinoxaline showed the increase in conductivity by higher percentage than any other systems, especially doped with D ‐sorbitol and surfynol. These showed the promising tendency to develop the annealing activated superior conductivity materials after further modifying the conducting film forming processes. However, PEDOT‐SPAAs doped with benzo‐1,4‐dioxan, imidazole and quinoxaline via annealed at 180°C for 10 min were found to be more conductive than doped with DMF, but still lower conductive than doped with D ‐sorbitol and surfynol. In terms of particle size, the stable aqueous dispersions of conducting polymers prepared were comparable to polystyrene sulfonate template. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Influence of the monomer feeding sequence on the structure and properties of thermotropic liquid‐crystalline poly(ester imide)s

A series of poly(ester imide)s mainly derived from N,N′‐hexane‐1,6‐diylbistrimellitimides, 4,4′‐dihydroxybenzophenone, and p‐hydroxybenzoic acid were synthesized by a direct polycondensation method in benzenesulfonyl chloride, N,N′‐dimethylformamide, and pyridine with different monomer feeding sequences. The molecular structures and properties of the resultant poly(ester imide)s were characterized with NMR, IR spectrometry, polarized light microscopy, wide‐angle X‐ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. The results showed that the monomer feeding sequences had a great effect on the sequential structure of the molecular chains of the copolymers and consequently on their liquid‐crystalline (LC) properties, fiber‐forming capability, and other properties. Thus, it is probable that one could obtain an LC poly(ester imide) with given properties by controlling the monomer feeding sequence during the polycondensation process. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Comparison of poly(o‐anisidine) and poly(o‐anisidine‐co‐aniline) copolymer synthesized by chemical oxidative method

In this study, poly(o‐anisidine) [POA], poly(o‐anisidine‐co‐aniline) [POA‐co‐A], and polyaniline [PANi] were chemically synthesized using a single polymerization process with aniline and o‐anisidine as the respective monomers. During the polymerization process, p‐toluene sulfonic acid monohydrate was used as a dopant while ammonium persulfate was used as an oxidant. N‐methyl‐pyrolidone (NMP) was used as a solvent. We observed that the ATR spectra of POA‐co‐A showed features similar to those of PANi and POA as well as additional ones. POA‐co‐A also achieved broader and more extended UV–vis absorption than POA but less than PANi. The chemical and electronic structure of the product of polymerization was studied using Attenuated Total Reflectance spectroscopy (ATR) and UV–visible spectroscopy (UV–vis). The transition temperature of the homopolymers and copolymers was studied using differential scanning calorimetry and the viscosity average molecular weight was studied by using dilute solution viscometry. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis of isomeric bis(amine anhydride)s for novel poly(amine imide)s by Pd-catalyzed amination of 4-chlorophthalic anhydride

Two novel bis(amine anhydride) monomers, N,N′-bis(3,4-dicarboxyphenyl)-1,4-phenylenediamine dianhydride I and N,N′-bis(3,4-dicarboxyphenyl)-1,3-phenylenediamine dianhydride II, were prepared via palladium-catalyzed amination reaction of 4-chloro-N-methylphthalimide with 1,4-phenylenediamine or 1,3-phenylenediamine, followed by alkaline hydrolysis of the intermediate bis(amine imide)s and subsequent dehydration of the resulting tetraacids. A series of new poly(amine imide)s were prepared from the synthesized dianhydride monomers with various diamines in NMP via conventional two-step method. FT-IR spectra of the poly(amine imide)s revealed that in the solid state, intermolecular and intramolecular hydrogen bonding (N-H?OC) are present. These polymers had glass transition temperatures in the range of 250-295 °C. The 10% weight loss temperature of the resulting poly(amine imide)s ranged from 539 to 560 °C in nitrogen. The poly(amine imide)s have the peel strength values ranging from 283 to 358 N/m. The poly(amine imide)s films were found to be transparent, flexible, and tough. The films had a tensile strength, elongation at break, and tensile modulus in the ranges 102-152 MPa, 11.3-19.6%, and 1.04-2.08 GPa, respectively.     

Synthesis and properties of PMR type poly(benzimidazopyrrolone‐imide)s

PMR type poly(benzimidazopyrrolone‐imide) or poly(pyrrolone‐imide) (PPI) matrix resin was synthesized using the diethyl ester of 4,4′‐(hexafluoroisopropylidene)diphthalic acid (6FDE), 3,3′‐diaminobenzidine, para‐phenylenediamine, and monoethyl ester of cis‐5‐norbornene‐endo‐2,3‐dicarboxylic acid (NE) in anhydrous ethyl alcohol with N‐methylpyrrolidone. The homogeneous matrix resin solution (40–50% solid) was stable for a storage period of 2 weeks and showed good adhesion with carbon fibers, which ensured production of prepregs. The chemical and thermal processes in the polycondensation of the monomeric reactant mixture were monitored by Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, etc. Thermosetting PPI as well as short carbon fiber‐reinforced polymer composites was accomplished at optimal thermal curing conditions. The polymer materials, after postcuring, showed excellent thermal stability, with an initial decomposition temperature > 540°C. Results of MDA experiments indicate that the materials showed > 70–80% retention of the storage modulus at 400°C and glass transition temperatures as high as 440–451°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1600–1608, 2001     

Novel organosoluble poly(amide‐imide‐imide)s synthesized from new tetraimide‐dicarboxylic acid by condensation with 4,4′‐oxydiphthalic anhydride, 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene,trimellitic anhydride,and various aromatic diamines

A new monomer of tetraimide‐dicarboxylic acid (IV) was synthesized by starting from ring‐opening addition of 4,4′‐oxydiphthalic anhydride, trimellitic anhydride, and 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene at a 1:2:2 molar ratio in N‐methyl‐2‐pyrrolidone (NMP). From this new monomer, a series of novel organosoluble poly(amide‐imide‐imide)s with inherent viscosities of 0.7–0.96 dL/g were prepared by triphenyl phosphite activated polycondensation from the tetraimide‐diacid with various aromatic diamines. All synthesized polymers were readily soluble in a variety of organic solvents such as NMP and N,N‐dimethylacetamide, and most of them were soluble even in less polar m‐cresol and pyridine. These polymers afforded tough, transparent, and flexible films with tensile strengths ranging from 99 to 125 MPa, elongations at break from 12 to 19%, and initial moduli from 1.6 to 2.4 GPa. The thermal properties and stability were also good with glass‐transition temperatures of 236–276°C and thermogravimetric analysis 10 wt % loss temperatures of 504–559°C in nitrogen and 499–544°C in air. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2854–2864, 2006     

Surface and electrical characteristics of poly(amide imide)–poly(dimethylsiloxane) nanocomposites

A series of poly(amide imide)–poly(dimethylsiloxane) (PDMS) nanocomposites were fabricated through the reaction of poly(amide imide), epoxysilane (coupling agent), and diethoxydimethylsilane (DEDMS) via a sol–gel process. Nanocomposite films were obtained through the hydrolysis and condensation of DEDMS in poly(amide imide) solutions. The existence of the condensation product of DEDMS in the poly(amide imide) matrix was confirmed with Fourier transform infrared (FTIR). The concentration of PDMS on the surface of the poly(amide imide) matrix was observed through a comparison of FTIR and attenuated total reflection spectra. The contact angle of the poly(amide imide)–PDMS composites increased more than 40° with respect to that of pure poly(amide imide). The alternating‐current (ac) breakdown strength was obtained through the measurement of the ac breakdown voltage at the temperature of liquid nitrogen. As the PDMS concentration in poly(amide imide) increased, the characteristics of the insulation breakdown improved greatly. The best ac breakdown strength was observed in a poly(amide imide)–epoxysilane (30 wt %) nanocomposite with 30 wt % PDMS. The samples at the temperature of liquid nitrogen were brittle, as in a glassy state. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 342–347, 2004     

Synthesis and characterization of alternate copolymers constructed by 1,3‐bis(diphenylsilyl)‐2,2,4,4‐tetraphenylcyclodisilazane units with oligo‐dimethylsiloxane segments

1,3‐Dichloro‐1,1,3,3‐tetraphenyldisilazane (DCTPS) with 71.6% yield was synthesized by the reaction of hexaphenylcyclotrisilazane (HPCT) with Ph₂SiCl₂ catalyzed by dibutyltin dilaurate. A ring‐closure reaction of DCTPS was carried out with BuLi in xylene–hexane mixture solvent; 1,3‐bis(chlorodiphenylsilyl)‐2,2,4,4‐tetraphenyl‐cyclodisilazane (BcPTPC) with 73.2% yield was obtained. Hydrolysis of BcPTPC in ether–triethylamine solvent resulted in 71.9% yield of 1,3‐bis(diphenylhydroxysilyl)‐2,2,4,4‐tetraphenylcyclodisilazane (B_HPTPC). By condensation polymerization of B_HPTPC with α,ω‐bis(diethylamino)‐oligo‐dimethylsiloxane, a kind of alternate copolymer constructed by 1,3‐bis(diphenylsilyl)‐2,2,4,4‐tetraphenylcyclodisilazane units with oligo‐dimethylsiloxane segments [P(BPTPC‐alt‐ODMS)] was synthesized. BcPTPC, B_HPTPC as well as P(BPTPC‐alt‐ODMS) were characterized by ²⁹Si‐NMR spectra, FT‐IR spectra, and elemental analysis. DGA study shows that P(BPTPC‐alt‐ODMS)s are thermally stable. The thermal decomposition onsets of P(BPTPC‐alt‐ODMS)s are all above 520°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1484–1490, 2005